Lithography or printing refers to any number of processes for creating a permanent image on a substrate. In semiconductor and micro-electromechanical systems (MEMS) manufacturing, photolithography is widely used as a method of patterning substrates. Recently, however, “soft lithography” methods have become popular, especially in prototyping applications.
Soft lithography is analogous to rubber stamping, but with greater pattern resolution, accuracy and image quality. Soft lithography also encompasses three-dimensional manufacturing processes in which a stamp with grooves or other surface indentations is brought into contact with a substrate and permanently stuck to it.
Compared to photolithography, soft lithography is inexpensive and straightforward. The utility of soft lithography has been somewhat limited, however, by a lack of readily available alignment tools. Often a stamp and substrate are only aligned by unaided human visual inspection.
There is a need therefore for alignment tools that are appropriate for soft lithography and three-dimensional manufacturing.